Entropy production and isotropization in Yang–Mills theory using a quantum distribution function

Abstract

We investigate thermalization process in relativistic heavy ion collisions in terms of the Husimi-Wehrl (HW) entropy defined with the Husimi function, a quantum distribution function in a phase space. We calculate the semiclassical time evolution of the HW entropy in Yang-Mills field theory with the phenomenological initial field configuration known as the McLerran-Venugopalan model in a non-expanding geometry, which has instabilty triggered by initial field fluctuations. HW-entropy production implies the thermalization of the system and it reflects the underlying dynamics such as chaoticity and instability. By comparing the production rate with the Kolmogorov-Sinaï rate, we find that the HW entropy production rate is significantly larger than that expected from chaoticity. We also show that the HW entropy is finally saturated when the system reaches a quasi-stationary state. The saturation time of the HW entropy is comparable with that of pressure isotropization, which is around 1 fm/c in the present calculation in the non-expanding geometry.

Hard gluon evolution in warming medium

“…[24] studied entropy density from decoherence as a function of time in heavy-ion collisions (see, also, Ref. [25,26]) and obtained a value of 15 < s dec < 20 fm −3 for 0 < t < 2 fm/c, which is in good agreement with our simple estimate for s(t o ). Also, in the simplified model we have described, we may define…”

Chaos of Wilson loop from string motion near black hole horizon

“…Chaos of Wilson loops is important for understanding meson dynamics and deconfinement transition. The charmonium suppression in heavy ion collisions may be understood by an entropic interquark force [28][29][30][31], and the chaos could provide the entropy in a manner similar to [32][33][34]. At the deconfinement a turbulent behavior is expected [35,36], and the scaling of excited meson numbers [37][38][39] can be attributed to the chaos of mesons [40] and chaos of the QCD string.…”

Hard gluon evolution in warming medium

“…Reference [24] studied entropy density from decoherence as a function of time in heavy-ion collisions (see, also, Ref. [25,26]) and included in the article's Creative Commons licence and your intended is not permitted by statutory regulation or exceeds the permitted use, you need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecomm ons.org/licenses/by/4.0/.…”